1. Field of the Invention
This invention relates to mechanisms for selectively altering the positioning of an inwardly depressable, outwardly biased, shiftable structure, such as a splined shaft, and for releasably locking such structure in either an inwardly depressed position or an outwardly shifted position thereof. More particularly, the invention provides an improved type of such a mechanism, which may be manually operated to selectively position the associated structure in either the inward or outward position of the latter merely through the application of an inwardly directed pressing force upon the end of an exposed plunger to move the associated structure to its inward position or the application of an inwardly directed force upon the exposed end of one or more control members to permit the associated structure to move to its outward position, with the mentioned plunger, control member(s) and associated structure being releasably interlocked in the conditions into which the same were last actuated and until a subsequent, selective, condition-changing actuation thereof.
The improved mechanism provided by the invention is especially adaptable for use with conventional, powered wheel, hub assemblies of combines or other normally self-propelled agricultural implements or the like, in which application the mechanism of this invention is substituted for the reversible disengaging plate typically heretofore employed in such hub assemblies. The purposes and advantages of utilizing the mechanism of this invention with such hub assemblies, in lieu of the reversible disengaging plate heretofore conventionally employed therewith, include the time saving and increased convenience of being able to selectively control the engaged or disengaged relationship of such a hub assembly to its associated shaft without needing to unbolt, remove, reverse, remount and rebolt a conventional disengaging plate, the adaptability of the improved mechanism to be confidently operated in the field and even in the dark, and the unique way in which such mechanism permits rapid selection between conditions of engagement and disengagement, in conjunction with releasable interlocking of the operative parts in either condition for the sake of reliability.
2. Description of the Prior Art
The most nearly analogous, known prior art is represented by the heretofore common employment of reversibly mounted plates having a projection on one side thereof, as a part of conventional constructions for power wheel, hub assemblies in combines or the like. A typical example of such use of reversible disengaging plates would be the Model 6 power wheel hub assembly marketed by the Warner Gear Division of Borg-Warner Corporation (and analogous products of other concerns). The here significant aspects of such prior devices are illustrated in FIGS. 1 and 2 of the accompanying drawings, and to a lesser extent in portions of FIGS. 4 and 5 of the accompanying drawings, to which reference is now made for explanatory purposes.
As shown in FIGS. 1 and 2, a typical, powered wheel, hub assembly of conventional construction, broadly designated 10, has a hub portion 12 having an annular flange 14 provided with openings 16 for use in bolt mounting a ground engaging wheel (not shown) thereto, and further has a generally cylindrical hollow housing 18 for containing internal gearing as at 36, 38 and other parts (not shown) through which the assembly 10 may be drivingly engaged with a power shaft 30 of the implement. The hub portion 12 will typically be rotatably mounted upon a spindle (not shown), in turn mounted upon the frame of the implement. The hub assemblies 10 further includes a cover 20 bolted to the housing 18 as at 22, and, in the most common prior construction, a reversible disengaging plate broadly designated 24 secured to the outer face of the cover 20 by means of bolts 26. The disengaging plate 24 is conventionally provided on one side thereof with a projection 28, which typically will be hollow or cuplike.
Referring next to the leftmost portion of FIGS. 4 and 5, it will be understood that the assembly 10 is normally associated with an axially shiftable power shaft 30 operably coupled with a hydraulic motor or other source of driving power (not shown) forming a part of the implement. The shaft 30 is provided with splines 32 adapted to operably interengage with grooves 34 in the internal face of a sun gear 36 forming a part of the hub assembly 10 and disposed within the housing 18 of the latter, the sun gear 36 usually having planet gears 38 associated therewith and also disposed within the housing 18. FIG. 4 illustrates the shaft 30 in an outwardly shifted, operative condition thereof in which the splines 32 are received within the grooves 34 of the sun gear 36 to effect a power coupled relationship between the shaft 30 and the hub assembly 10. In FIG. 5, the shaft 30 is depicted in an inwardly depressed condition thereof in which the splines 32 are not engaged with the grooves 34 of the gear 36, which is known as the disengaged position in which no power coupling exists between the shaft 30 and the hub assembly 10. As those familiar with the involved general class of device will be aware, means such as one or more springs (not shown) will be provided as a part of the overall assemblage for yieldably biasing the shaft 30 in an outward direction (i.e., toward the right in the figures of the accompanying drawings), or toward the operative position of the shaft 30 illustrated in FIG. 4, rather than the disengaged position of the shaft 30 illustrated in FIG. 5.
Conventional hub assemblies 10 also typically include a plunger, which may be of somewhat different proportions and construction than the hereinafter described plunger 50 employed in the improved mechanism of this invention, but which is also disposed in axial alignment with the outer end 40 of the shaft 30, is in rotatable engagement with the latter (usually via an intervening thrust washer), and is adapted to be axially shifted along with the shaft 30 either outwardly under the influence of the bias upon the shaft 30 or inwardly in opposition to such bias.
The conventional disengaging plate 24 as shown in FIG. 1 is in the orientation thereof which permits the shaft 30 to shift outwardly into its operative position under the influence of the outward bias thereon, it being understood that the disposition of the hollow projection 28 upon the outer face of the plate 24, when mounted as depicted in FIG. 1, permits the outer end of the mentioned plunger to move into the cup 28 sufficiently for the bias upon the shaft 30 to move it outwardly into its operative position. FIG. 2 illustrates the conventional hub assembly 10 with its disengaging plate 24 mounted in a reversed orientation thereof disposing the projection 28 on the inner side of the plate 24 and, typically, in inwardly extending relationship through an associated central aperature (as at 42 in FIGS. 4 and 5) in the cover 20 aligned with the axes of the shaft 30 and its associated plunger. With the plate 24 mounted on the cover 20 as last described, the projection 28 pushes the mentioned plunger inwardly to shift the shaft 30 inwardly to the disengaged position of the latter.
Such conventional construction hub assembly utilizing a reversible disengaging plate 24 having a projection 28 on one side thereof is effective in permitting an engagement or disengagement of the power coupling between the shaft 30 and the hub assembly 10 to be ultimately accomplished. However, in order to accomplish such result with that structure, for instance changing from the power engaged condition of FIG. 1 to the power disengaged position of FIG. 2, it is necessary to first remove the bolts 26, then remove the diengaging plate 24, then reverse the orientation of the disengaging plate 24, and then reinstall the bolts 26 to mount the plate 24 upon the cover 20 in its reversed orientation. Such operations are obviously time consuming at best and may be quite inconvenient to perform when the implement is in the field, where it typically will be when such a change is to be made. Aside from needing a proper tool to remove and reinstall the bolts 26, there is always the danger of dropping and losing one or more of the parts being handled under field conditions. All of such disadvantages of the conventional construction employing a bolt mounted, reversible disengaging plate 24 are significantly increased when the required operations must be performed in the dark at the end of a long day of field work, as is also typical.